Apparatus for bending a glass sheet

ABSTRACT

A glass sheet is heated to a forming temperature in a heating furnace, the heated glass sheet is conveyed along a conveying plane defined by a plurality of rollers of a roller conveyer, and is moved up and down on the rollers according to the position of the glass sheet to curve a part of the conveying plane with respect to the glass sheet conveying direction to bend the glass sheet to have a desired curvature by its own weight. The rollers are curved rollers.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims the benefit of priorityunder 35 U.S.C. §120 from U.S. Ser. No. 10/952,753, filed Sep. 30, 2004,which is a continuation of U.S. Ser. No. 10/389,995, filed Mar. 18,2003, now U.S. Pat. No. 6,843,074, issued Jan. 18, 2005, which is acontinuation of PCT/JP02/07268, filed Jul. 17, 2002, and claims thebenefit of priority under 35 U.S.C. §119 from Japanese PatentApplication Number 2001-217759, filed Jul. 18, 2001, the entire contentsof each which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to an apparatus for bending a glass sheetand, more particularly, to an apparatus for bending a glass sheet usedfor transporting machines such as automobiles, vessels, trains andaircrafts, buildings and other various applications.

BACKGROUND ART

The inventors of the present application proposed in JP-A-2000-72460 aforming apparatus for bending a glass sheet heated to a temperatureclose to the softening point in a heating furnace into a glass sheethaving a desired curvature. This apparatus conveys a glass sheet heatedin the heating furnace, along a conveying plane defined by a pluralityof rollers of a roller conveyer, and by moving the rollers up and downaccording to the position of the glass sheet, a part of the conveyingplane is bent with respect to the glass sheet conveying direction andthe glass sheet is bent to have a desired curvature.

Meanwhile, U.S. Pat. No. 4,123,246 discloses an apparatus for bending aglass sheet heated to a temperature close to the softening point in aheating furnace, by conveying the glass sheet on a roller conveyerconstituted by a plurality of curved rollers each curved with respect tothe direction perpendicular to the glass sheet conveying direction.

According to the apparatus disclosed in the above two documents, thesoftened glass bends down by its own weight along the curved plane,whereby the glass sheet can be bent according to the curved conveyingplane.

The conventional apparatus for bending disclosed in U.S. Pat. No.4,123,246 had a problem that although it could form a glass sheet tohave a curved plane with respect to the direction perpendicular to theglass sheet conveying direction, it could not form a glass sheet to havea curved plane with respect to the glass sheet conveying direction. Thisapparatus has a conveying plane curved only with respect to onedirection, and therefore, it is difficult to form a complicatedly curvedglass having a plane curved with respect to two directions.

It is an object of the present invention to solve the above problems ofthe conventional techniques, and to provide a curved roller whosecurvature can optionally be changed, and an apparatus for bending aglass sheet, so that a glass sheet having a complicatedly curved shapecan be produced.

DISCLOSURE OF THE INVENTION

The present invention provides an apparatus for bending a glass sheet,comprising a heating furnace to heat a glass sheet to a bendingtemperature, and a roller conveyer having a plurality of rollers toconvey the heated glass sheet along a conveying plane defined by therollers, said rollers being movable up and down according to theposition of the glass sheet, to have a part of said conveying plane bentwith respect to the conveying direction of the glass sheet thereby tolet the glass sheet bend by its own weight to have a desired curvature;characterized in that said rollers are curved rollers.

Further, the present invention provides a curved roller comprising avariable curvature rod having a first link structure to realize apredetermined mono-curvilineal shape, and a second link structureprovided beside it to realize a predetermined mono-curvilineal shape,and a ring roller rotatable about said variable curvature rod as arotation axis;

wherein said first and second link structures are each constituted by aplurality of link members connected via gear portions so as to beswingable,each of said link members has two pivot pins located at a constantpitch, and the link members constituting said first link structure, andthe link members constituting said second link structure, share saidpivot pins with half pitch shifted from each other.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1: A perspective view illustrating an embodiment of an apparatusfor bending a glass sheet according to the present invention.

FIG. 2: A view illustrating up/down movement of curved rollers accordingto the position of a glass sheet being conveyed.

FIG. 3: A view illustrating a mechanism for moving a curved roller upand down.

FIG. 4: A view illustrating a curved roller of a first embodiment.

FIG. 5: An enlarged cross-sectional view of a substantial part of thecurved roller shown in FIG. 4.

FIG. 6: A view illustrating a curved roller of a second embodiment.

FIG. 7: An enlarged cross-sectional view of a substantial part of thecurved roller shown in FIG. 6.

FIG. 8: A vertical cross-sectional view of the curved roller shown inFIG. 6.

FIG. 9: A diagram of a substantial part of a curved roller shown in FIG.6.

FIG. 10: A view illustrating a curved roller of a third embodiment.

FIG. 11: A side view illustrating another embodiment of the curvedroller.

FIG. 12: An enlarged view of the substantial part of FIG. 11.

FIG. 13: A perspective view illustrating an apparatus for bending aglass sheet by its own weight.

BEST MODE FOR CARRYING OUT THE INVENTION

Now, preferred embodiments of an apparatus for bending a glass sheet,according to the present invention, will be described with reference todrawings.

FIG. 1 is a perspective view illustrating an embodiment of an apparatusfor bending a glass sheet. As illustrated in the view, an apparatus 10for bending is constituted by a heating furnace 16, a forming zone 16 aand an air-cooling/tempering apparatus 16 b as main components. Further,the driving control of each part of the apparatus 10 for bending iscarried out by a motion controller CNT constituted by e.g. a computer.

Firstly, the bending step of a glass sheet 18 by the apparatus 10 forbending, will be described. The glass sheet 18 before bending ispositioned to a conveying position at the entrance of the heatingfurnace 16, and is conveyed into the heating furnace 16 by a rollerconveyer, not shown. Then, the glass sheet 18 is heated by a heater inthe heating furnace 16 while it is conveyed in the heating furnace 16,whereby it is heated up to the bending temperature (about from 600 to700° C.) at the exit of the heating furnace 16. The glass sheet 18heated up to the bending temperature, is conveyed by a roller conveyer13 a for bending to the forming zone 16 a provided on a downstream sideof the heating furnace 16.

Rollers constituting the roller conveyer 13 a, are each a curved rollercurved vertically downward in a convex form so as to form, in the glasssheet 18, a curved plane curving with respect to the directionperpendicular to the conveying direction. And further, by moving up anddown each roller of the roller conveyer 13 a like the propagation of awave while the glass sheet 18 is conveyed in the forming zone 16 a, theglass sheet 18 will have a curved plane curving with respect to theconveying direction. As a result, the glass sheet 18 can be formed tohave a curved plane having a curvature with respect to two directions.Here, rollers curving vertically upward in a convex form, can also beemployed, but from a viewpoint of stability of conveying the glass sheet18, rollers curving vertically downward in a convex form, are moreexcellent.

The bent glass sheet 18 is conveyed from the exit of the forming zone 16a into the air-cooling/tempering apparatus 16 b by a roller conveyer 13b of the air-cooling/tempering apparatus 16 b, to be tempered byair-cooling. The air-cooling/tempering apparatus 16 b has an upperblowing head 17 a and a lower blowing head 17 b disposed sandwiching theroller conveyer 13 b, and the glass sheet 18 is cooled and tempered byair blown from the blowing heads 17 a and 17 b towards the glass sheet18.

Here, the cooling performance of the air-cooling/tempering apparatus 16b is appropriately set depending on e.g. a thickness of the glass sheet18. The glass sheet 18 tempered by air-cooling, is conveyed to theinspection apparatus (not shown) as the next step by a roller conveyer13 c from the exit of the aircooling/tempering apparatus 16 b. This isall about the bending step of the glass sheet 18 in the apparatus 10 forbending.

Curved rollers 12A to 12M, . . . , constituting the roller conveyer 13(13 a, 13 b and 13 c) shown in FIG. 2, are each independently rotated bya rotation driving means (not shown), and each independently moved upand down by an elevating means (not shown). As illustrated in (A) to (E)in the view, the conveying plane of the glass sheet 18 constituted bythe rollers, deforms like the propagation of a wave from upstream sideto downstream side. As a result, the curvature of the glass sheet 18,gradually increases as it is conveyed from upstream side to downstreamside. Here, the driving of these rotation driving means and elevatingmeans, are controlled by a motion controller CNT in FIG. 1.

FIG. 3 is a diagram illustrating a rotation driving means and aelevating means of each of the curved rollers 12A to 12M, . . . . Here,since the rotation driving means and the elevating means of the curvedrollers 12A to 12M, . . . , have the same structure, FIG. 3 illustratesonly the structure of a curved roller 12A, and the description regardingthe structure of other curved rollers 12B to 12M, . . . , is omitted forconvenience.

The curved roller 12A is rotatably supported at its both ends viabearings 32, 32 by a movable frame 30 formed to have a concave shape.Further, to the left end of the curved roller 12A in FIG. 3, a gear 34is attached as shown in FIG. 4, and the gear 34 is engaged with a gear36 at a side of a servo motor 38. Accordingly, by driving the servomotor 38, the curved roller 12A is rotated at a predetermined angularspeed. This is all about the structure of the rotation driving means.

On the other hand, the movable frame 30 is, as illustrated in FIG. 3,supported at its both sides by a fixed frame 42 via a LM (linear motion)guide so as to be movable up and down. This LM guide comprises a guiderail 44 disposed vertically at a side of the movable frame 30, andlinear motion guides 46, at a side of the fixed frame 42, engaged withthis guide rail 44.

Further, at both ends of a lower portion of the movable frame 30, racks48, 48 are provided so as to protrude downward therefrom, and pinions50, 50 are engaged with the racks 48, 48. The pinions 50, 50 are fixedto a rotational shaft 52 provided horizontally, and the rotational shaft52 is supported by the bearings 54, 54 at its both ends, and its leftend portion in FIG. 3 is connected to a spindle 58 of a servo motor 56.Therefore, when the servo motor 56 rotates the rotation shaft 52, therotational movement is converted to a linear movement by the effect ofthe pinions 50 and the racks 48, and a curved roller 12A is moved up anddown together with the movable frame 30. That is all about the structureof the elevating means. Here, numeric symbols 60, 62 in FIG. 3 indicateheaters provided in the heating furnace 16. Further, in a case of anout-furnace apparatus for bending having curved rollers 12A to 12M, . .. , provided outside the furnace, the heaters 60, 62 are not provided.

The rotation driving means and the elevating means described above, areprovided for all of other curved rollers 12A to 12M, . . . , and theservo motors 38, 56 for those means are controlled by a motioncontroller CNT in FIG. 1.

When the type of the glass sheet 18 is input from an external inputmeans not shown, the motion controller CNT prepares angular speedcontrol data and up/down movement control data of the curved rollers 12Ato 12M, . . . , which correspond to the curvature of the glass sheet 18of the type. Then, the motion controller CNT controls the servo motors38 based on the angular speed control data prepared, and controls theservo motors 56 based on the up-down movement control data. Namely, themotion controller CNT carries out multi-axis control of the curvedrollers 12A to 12M, . . . , so that the glass sheet 18 is bent to have adesired curvature during the conveyance by the curved rollers 12A to12M, . . . .

Secondly, the multi-axis control method of the curved rollers 12A to 12Mby the motion controller CNT will be described. Basic up/down movementof the rollers is such that according to the conveyance of a glass sheetG, down-movement and up-movement of the curved rollers 12A to 12M, . . ., are carried out sequentially in this order.

The curved rollers 12A to 12M, . . . , subjected to multi-axis controlby the motion controller CNT, behave such that for example asillustrated in FIG. 2 (A), when the heated glass sheet 18 reaches theentrance side curved roller 12A, all the curved rollers 12A to 12M, . .. , are at the top position, and the curved conveying path 14 defined bythe curved rollers 12A to 12M, . . . , is curving only with respect to aB direction (the direction perpendicular to the glass sheet conveyingdirection) in FIG. 1. Thereafter, when the glass sheet 18 is furtherconveyed, the curved rollers 12B and 12C move down.

Then, when the glass sheet 18 is conveyed as illustrated in FIG. 2(B),the curved rollers 12D to 12F move down, whereby among the conveyingpath 14 defined by the curved rollers 12A to 12M, . . . , a curvedconveying path defined by the curved rollers 12D to 12F deforms to curvein a gentle downward convex form having a large curvature radius.Namely, the curved conveying path deforms with respect to the directionof A (glass sheet conveying direction) in FIG. 1. Consequently, when theglass sheet 18 passes on the curved rollers 12D to 12F, the glass sheet18 bends downwardly by its own weight along a conveying plane defined bythe curved rollers 12D to 12F, and deforms to have a shape along thecurved plane. Consequently, the glass sheet 18 is formed to be acomplicatedly curved glass.

Thereafter, when the glass sheet 18 is further conveyed as illustratedin FIG. 2(C), the curved rollers 12F to 12H move down more deeply thanthe previous curved rollers 12D to 12F, whereby a curved conveying pathdefined by the curved rollers 12F to 12H deforms to have a curved shapehaving a smaller curvature radius (sharply curved) than the previouscurved conveying path. Consequently, when the glass sheet 18 passes onthe curved rollers 12F to 12H, the glass sheet 18 further bendsdownwardly along the conveying plane defined by the curved rollers 12Fto 12H, and is deformed to have a shape along the curved plane.

Thereafter, when the glass sheet 18 reaches a substantially middle pointof the curved conveying path as illustrated in FIG. 2(D), the curvedrollers 12H to 12J move down more deeply than the previous curvedrollers 12F to 12H, whereby a two-directional conveying plane defined bythe curved rollers 12H to 12J, deforms to have a curved shape having asmaller curvature radius than the previous curved plane. Consequently,when the glass sheet 18 passes on the curved rollers 12H to 12J, theglass sheet 18 bends downwardly along the conveying plane defined by thecurved rollers 12H to 12J, and is deformed to have a shape along theconveying plane.

Thereafter, when the glass sheet 18 reaches a downstream side of thecurved conveying path as illustrated in FIG. 2(E), the curved rollers12J to 12L move down more deeply than the previous curved rollers 12H to12J, whereby a conveying plane defined by the curved rollers 12J to 12Ldeforms into a curved shape having a curvature corresponding to thefinally obtainable curvature of the glass sheet 18. Consequently, whenthe glass sheet 18 passes on the curved rollers 12J to 12L, it isdeformed to have a shape along the conveying plane, whereby it is bentto have a desired curvature. That is all about the bending operation ofthe glass sheet 18 by the above curved rollers 12A to 12M.

As described above, the apparatus 10 for bending of this embodimentemploys, as rollers of a roller conveyer in an apparatus for bending aglass sheet with respect to the glass sheet conveying direction bymoving the rollers up and down, curved rollers 12 each having thesurface curved with respect to the direction perpendicular to the glasssheet conveying direction. Consequently, a complicatedly curved glasscurved along the conveying direction and along the horizontal directionperpendicular to the conveying direction, can be produced.

In the following, an embodiment of the curved roller 12 will bedescribed.

FIG. 4 and FIG. 5 show a curved roller 12 of the first embodiment. Inthe curved roller 12, a plurality of ring rollers 72, 72, . . . , arerotatably supported by a guide shaft 70 preliminarily bent to have apredetermined curvature. A ring roller 72 is constituted by a rollerbody 74 and a color 76. The roller body 74 is formed to have a tubularform, and has in its central portion a large diameter perforation 78opening to one end and a small diameter perforation 80 opening to theother end. The small diameter perforation 80 is formed to have a largerdiameter than the outer diameter of the guide shaft 70. A bush 82 isinserted in the large diameter perforation 78, and the bush 82 is fittedto the guide shaft 70. Consequently, the plurality of ring rollers 72,72, . . . , are rotatably supported by the guide shaft 70.

Further, annular ribs 84, 84 are formed on both ends of the roller body74 of the ring roller 72, and threaded holes 86, 86, . . . , are formedat two positions in the outer peripheral surface of each of the ribs.Further, a color 76 is fitted to the outer peripheral surface of theroller body 74 by e.g. shrinkfitting. The color 76 has a widthsubstantially same as the total width of the roller body 74, and a hole88 is formed in the extension of a threaded hole 86 of the roller body74.

Adjacent ring rollers 72, 72 are connected each other by an elastictubular member 90 made of rubber attached to their circular ribs 84, 84.Namely, the elastic tubular member 90 has perforations 92 at both ends,and is connected by screws 94 each inserted in a perforation 92 andscrewed in the threaded hole 86 of the rib 84. Such elastic tubularmember 90 has an inflated portion 90A formed in the entire circumferenceat the middle portion in its width direction.

Further, the curved roller 12 has a sprocket housing 96 at a left end ofthe ring roller 72. The sprocket housing 96 is rotatably supported bythe guide shaft 70 via bushes 98. The sprocket housing 96 has a circularrib 100 formed on a ring roller 72 side end, and threaded holes 102 areformed at two positions in the circular rib 100. To each of the circularrib 100 and the circular rib 84 of the ring roller 72, an end portion ofthe elastic tubular member 90 made of rubber is fitted. The screws 94each inserted in the perforation 92 of the elastic tubular member 90 arescrewed in the threaded hole 86 of the circular rib 84, and screws 104each inserted in the perforation 92 of the elastic tubular member 90 arescrewed in the threaded hole 102 of the circular rib 100, whereby thesprocket housing 96 and the ring roller 72 are mutually connected.Further, a gear 34 is fixed to the sprocket housing 96.

Here, the connection between the sprocket housing 106 and the ringroller 72 on a right side in FIG. 4, is also achieved by an elastictubular member 90 made of rubber in the same manner as in the connectionbetween the sprocket housing 96 and the ring roller 72 on a left side,and its connection structure is also the same. Therefore, thedescription will be omitted.

The curved roller 12 thus constituted, has a guide shaft 70preliminarily curved, whereby the curved conveying path 14 curved withrespect to the direction perpendicular to the glass sheet conveyingdirection can be formed. Further, in this curved roller 12, when thegear 34 is rotated by a servo motor 38, the torque is transmitted to thering rollers 72, 72, . . . , via elastic tubular members 90, 90, . . . .Accordingly, the conveying power of the glass sheet 18 can be obtained.

FIG. 6 to FIG. 8 show a curved roller 120 of the second embodiment. Thecurved roller 120 has a rod-shaped curved rod 124 comprising a pluralityof oval link members 122, 122, . . . , wherein adjacent link members122, 122 are swingably connected one another via the gear portions 123,123 in FIG. 7, and a plurality of ring rollers 126 rotatably fitted onthe curved rod 124 and rotatable about the axial center P of the curvedrod 124.

Further, to a link member 122 at left end side of the curved rod 124 inFIG. 6, a rod portion 172 of a hydraulic cylinder 170 for moving thelink member 122 up and down, is connected via a linear motion guidemember 174. Further, the link member 122 on the left end side in FIG. 6is provided on the top end of the rod portion 172 via a pin 176 so as tobe swingable in a vertical direction. Here, instead of the hydrauliccylinder 170, an elevating mechanism employing a servo motor and a ballscrew device, may be applied. By this elevating mechanism, an up/downstroke control of the link member 122 will become possible.

The curved rod 124 is constituted by a first link structure 122 and asecond link structure 130. As illustrated in FIGS. 8 and 9, adjacentlink members 122-1, 122-2 are swingably supported by a link member 132via pins 130, and each of the pins 130 is inserted in pinholes 122 a,132 a of the link members 122-1, 132-2, whereby they are swingablysupported by the ring roller 126. A link member 132-1 has an identicalshape with the link member 122-1, and is attached to the link member122-1 at a position shifted by a half length of the link member 122-1,and connected with an adjacent link member 132-1 via a gear portion, notshown.

Accordingly, when the left end portion of the link structure 122 at theleft end of the FIG. 6 is elevated by elevating the rod portion 172 ofthe hydraulic cylinder 170 shown in FIG. 6, the left end link member isrotated about the pin 176 in the clockwise direction, and the rotationpropagates via gear portions 123, 123 to adjacent link members 122-1,132-1, 122-2, 132-2, . . . . By this operation, the crossing anglesdefined by adjacent pairs of link member 122-1, 132-1, 122-2, 132-2, . .. , gradually increase while maintaining the all angles to be equal.Accordingly, the curved rod 124 is curved downward in a convex formhaving a single curvature.

When the curved rod 124 is curved, cores 126A and each of the ringrollers 126, 126, . . . , swing along the curved rod 124, and as aresult, the curved roller 120 is curved with a single curvature withrespect to the direction perpendicular to the glass sheet conveyingdirection. Further, by adjusting the amount of elevation given to thecurved rod 124, the curvature of the curved rod 124, namely thecurvature of the curved conveying path, can be adjusted. Accordingly, adifferent type of glass sheet having a different model (curvature) canbe formed by a single type of curved rollers 120. By this effect, thejob change of the curved roller accompanied by the change of the glasssheet model, is substantially eliminated.

Here, a gear 134 is fixed to the ring roller 126 on left end side inFIG. 6, and with the gear 134, a driving gear 140 connected to a spindle138 of a servo motor 136, is engaged. Further, the ring rollers 126,126, . . . , are connected by elastic tubular members 142, 142, . . . ,as shown in FIG. 7. Accordingly, by applying the torque of the servomotor 136 to the ring roller 126 at a left end side in FIG. 6, all ofthe ring rollers 126, 126, . . . , are rotated whereby the conveyingpower for a glass sheet can be obtained. Further, the servo motor 136 isinstalled on a platform 178 attached to the link member 122 at the leftside end in FIG. 6 so as to move up and down together with the linkmember 122.

FIG. 10 illustrates a curved roller 150 of the third embodiment. Thecurved roller 150 has a flexible shaft 152 constituted to be bendable, aplurality of ring rollers 154, 154, . . . , fitted on the flexible shaft152 so as to rotate about the axial center of the flexible shaft 152,and a link structure 124 (corresponding to the conveying plane curvingmeans in Claim) for bending the flexible shaft 152 into a desiredcurvature to thereby curve the conveying plane defined by the pluralityof ring rollers. The curved rod 124 and the flexible shaft 152 areconnected via bearings 156. By curving the curved rod 124, the flexibleshaft 152 is bent along the curved rod 124, and the conveying planedefined by the ring rollers 154, 154, . . . , is curved with respect tothe direction perpendicular to the glass sheet conveying direction.

Further, to the left end portion of the flexible shaft 152 in FIG. 10, agear 158 is fixed. And with the gear 158, a driving gear 164 connectedto a spindle 162 of a servo motor 160, is engaged. Further, the ringrollers 154, 154, . . . , are connected via annular connecting members166. Accordingly, by providing a torque of the servo motor 160 to theflexible shaft 152, all of the ring rollers 154, 154, . . . , arerotated whereby the conveying force for the glass sheet can be obtained.The left end portion of the curved rod 124 in FIG. 10 is connected to aspindle 184 of a servo motor 182 via a ball screw device 180 which movesup and down. Further, to a nut portion 186 of the ball screw device 180,a platform 188 is horizontally connected, and a servo motor 160 ismounted on this platform. Therefore, when the nut portion 186 is movedup and down by rotating the ball screw device 180 by the servo motor182, the curved rod 124 is moved up and down together with the servomotor 160 to create a single curvature.

FIG. 11 and FIG. 12 show another embodiment of the curved roller. Sincethe roller portion as the main portion for defining the conveying planeof the curved roller 190, has the same construction as the curved roller12 shown in FIG. 5, members same as or similar to the members of thecurved roller 12 are identified with the same numeric symbols. The guideshaft 70 (FIG. 5) of the curved roller 190, is made of a material (forexample S45C) bendable due to an elastic deformation and formed to havea straight rod-shape. A plurality of ring rollers 72, 72, . . . , fittedon the guide shaft 70, are each connected with an adjacent one via anelastic tubular member made of a rubber, to constitute a single hollowroller structure 192 as a whole.

Both ends 70A of the guide shaft 70 are protruded from both ends 192A ofthe hollow roller structure 192 by a predetermined length as shown inFIG. 12, and an outer cylinder 194 covering a protruded end 70A, isdisposed. One end 194A of the outer cylinder 194, is connected to an end192A of the hollow roller structure 192, and supported by a supportingmember 198 via a bearing 196. Further, the bearing 196 is supported bythe supporting member 198 via a horizontally implanted pin 199, so thatthe outer cylinder 194 and the end 70A of the guide shaft 70 (FIG. 5)can be bent with an elasticity as shown by double dotted lines in FIG.12. Here, the supporting member 198 is fixed to a stand 200 supportingthe entire curved roller 190.

The other end 194B of the outer cylinder 194, is connected to a bracket204 via a bearing 202. The bearing 202 is rotatably connected to thebracket 204 via a horizontally implanted pin 206, whereby the bending ofthe outer cylinder 194 and the end 70A of the guide shaft 70 indicatedby double dotted lines in FIG. 12, can be permitted when the bracket 204is elevated.

To a lower portion of the bracket 204, a slider 208 is connected, andthe slider 208 is connected to a feed screw device 210 for moving up anddown the slider 208. The feed screw device 210 is driven by a drivingforce of a motor 212. Here, the feed screw device 210 is fixed to a legportion 201 of the stand 200.

Further, the other end 194B of the outer cylinder 194, is connected toan output shaft 220 of a motor 218 via a gear 214 and a gear 216. Inthis construction, when the motor 218 is driven, the torque istransmitted via the gear 216, the gear 214 and the outer cylinder 194 tothe hollow roller structure 192, whereby the hollow roller structure 192is rotated. Here, the gear 214 is rotatably supported by the guide shaft70, and the gear 216 is rotatably supported by a bearing portion 224 ofan inclination guide frame 222.

The inclination guide frame 222 has one end attached to the supportingmember 198 via pins 226, 226 so as to be inclined, and has the bearingportion 224 formed at the other end. Therefore, the inclination guideframe is inclined according to the bending of the outer cylinder 194 andthe end portion 70A of the guide shaft 70 shown by the double dottedlines in FIG. 12. Further, a stopper pin 228 is provided underneath theinclination guide frame 222, and a head portion 229 of the stopper pin228 is in contact with a stopper plate 230 of the leg portion 201 tolimit the inclination angle of the inclination guide frame 222, wherebybending amounts of the outer cylinder 194 and the end portion 70A (referto double dotted lines in FIG. 12) of the guide shaft 70 are limited.

When the slider 208 is elevated by the feed screw device 210 driven bythe motor 212, the force is transmitted via the bracket 204 to the pin206, and via this pin 206, the outer cylinder 194 is pushed upward as itis pivoted by the pin 199. By this operation, the outer cylinder 194 andthe end portion 70A of the guide shaft 70 are bent as illustrated by thedouble dotted lines in FIG. 12, and according to this, the hollow isroller structure 192 is bent downwardly in a convex form as illustratedby double dotted lines in FIG. 11. Accordingly, the curved roller 190 iscurved. The curving angle of the curved roller 190 can be adjusted bycontrolling the elevated position of the slider 208.

Here, since the pin 206 as a power point is apart by a predetermineddistance from the pin 199 as a pivotal point, the curved roller 190 canbe curved with a small power without applying an unreasonable power.Further, the right end portion of the guide shaft 70 in the Figure, hassubstantially the same construction as the above construction. Namely,the driving means for moving up and down the outer cylinder 194 and theguide shaft 70, are provided at both ends of the guide shaft 70, whilethe rotating driving means for rotating the outer cylinder 194,is-provided only at one end of the guide shaft 70. However, as the caserequires, the rotating driving means may be provided at both ends of theguide shaft 70, or a means for moving the outer cylinder 194 and theguide shaft 70 up and down may be provided only at one end of the guideshaft 70 wherein the guide shaft 70 at the other end may only besupported so as to be movable up and down by employing e.g. LM guide.

Further, in FIGS. 11 and 12, the hollow roller structure 192 and theouter cylinder 194 are connected via the bearing 196, and the hollowroller structure 192 is rotated by rotating the outer cylinder 194.However, since a very large load is applied to the bearings 196 and 202in order to curve the guide shaft 70 (FIG. 5), a high durabilitywithstanding the load is required to these bearings. For this problem,it is preferred to attach a gear at the end of the hollow rollerstructure 194 so that the torque of the motor is transmitted to the endof the hollow roller structure 192 without the bearing 196. It becomesunnecessary to use the outer cylinder 194, and the bearings 196 and 202becomes unnecessary, whereby the above problem will be solved.

In the above, description has been made with respect to an example of anapparatus for bending which moves up and down each roller of the rollerconveyer independently, but the present invention is not limitedthereto. Namely, the curved roller 120, 150 or 190 illustrated in theFIGS. 6 to 12 may be applied to the apparatus for bending shown in FIG.13. Further, these curved rollers may be installed not only in theforming zone but also in the cooling zone where theair-cooling/tempering apparatus is installed, or in the subsequent step.Namely, by installing the curved rollers between the upper and lowerblowing ports, the glass sheet is pushed toward the curved rollers by awind pressure of the air blown from the blowing ports, whereby not onlythe bending by its own weight in the forming zone, but also the bendingby the wind pressure in the air-cooling zone can be carried out. Theapparatus 10 for bending a glass sheet shown in FIG. 13, has a rollerconveyer 13 constituted by a plurality of curved rollers 12, 12, . . . .The specific construction of each of the curved rollers 12, 12, . . . ,is as illustrated in FIGS. 6 to 12. The curved rollers 12, 12, . . . ,are disposed substantially in parallel to each other, and a curvedconveying path 14 curving along the horizontal direction (the directionindicated by an arrow B in FIG. 13) perpendicular to the glass sheetconveying direction (the direction indicated by an arrow A in FIG. 13),is formed in a roller conveyer 13. The conveying path 14 is formed fromthe exit of the heating furnace 16 toward the air-cooling/temperingapparatus, not shown, installed outside the heating furnace 16. Thedriving control of each part is carried out by a motion controller CNT.

Further, the curvature of the curved conveying path 14 with respect tothe direction of arrow B, gradually increases from the upstream side ofthe curved conveying path 14 towards the downstream side, and becomes acurvature corresponding to the curvature of the produced glass sheet atthe most downstream side of the curved conveying path 14. Therefore, theglass sheet 18 conveyed in the heating furnace 16 is bent gradually byits own weight according to the curvature of the curved conveying path14, and bent to have a curvature corresponding to the produced glasssheet at the most downstream side of the curved conveying path 14.

INDUSTRIAL APPLICABILITY

As described above, according to the apparatus for bending a glass sheetaccording to the present invention, a curved roller which has a rollersurface curved with respect to the direction perpendicular to the glasssheet conveying direction, is applied as a roller for the apparatus forbending a glass sheet with respect to the conveying direction by movingrollers of a roller conveyer up and down, whereby a complicatedly curvedglass having a curved plane with respect to two directions can beformed.

The entire disclosure of Japanese Patent Application No. 2001-217759tiled on Jul. 18, 2001 including specification, claims, drawings andsummary is incorporated herein by reference in its entirety.

1. An apparatus for bending a glass sheet, comprising a heating furnaceto heat a glass sheet to a bending temperature, and a roller conveyerhaving a plurality of rollers to convey the heated glass sheet along aconveying plane defined by the rollers, said rollers being movable upand down according to the position of the glass sheet, to have a part ofsaid conveying plane sheet bent with respect to the conveying directionof the glass sheet thereby to let the glass sheet bend by the weightthereof to have a desired curvature wherein said rollers are curvedrollers, each of said curved rollers having a flexible shaft capable ofbeing bent, a plurality of ring rollers are provided which are rotatableabout the flexible shaft as the rotation axis, a plurality of ringrollers; and a curving rod for supporting the flexible shaft and forcurving said conveying plane defined by a plurality of said ringrollers, by flexing the curving rod and thereby flexing the flexibleshaft to have a desired curvature along the curving rod.
 2. Theapparatus for bending a glass sheet according to claim 1, wherein saidcurving rod has a variable curvature rod having a first link structurefor realizing a desired mono-curvilineal shape, and a second linkstructure provided beside the first link structure for realizing adesired mono-curvilineal shape; said first and second link structurescomprising a plurality of link members linked via gear portions so as tobe swingable, each of said link members having two pivot pins located ata constant pitch, and wherein the link members comprise said first linkstructure, and the link members comprising said second link structureshare said pivot pins with a half pitch shifted from each other.
 3. Theapparatus for bending a glass sheet according to claim 1, wherein saidplurality of ring rollers are connected one another by a plurality offlexible tubular members.
 4. The apparatus for bending a glass sheetaccording to claim 1, wherein said curved rollers are arranged in acooling zone.